[U-Boot] [PATCH 4/9] ARM: socfpga: Bundle U-Boot fitImage into SFP on Arria10

[Marek Vasut]

On 11/26/2018 11:30 AM, Chee, Tien Fong wrote:
> On Fri, 2018-11-23 at 13:40 +0100, Marek Vasut wrote:
>> On 11/23/2018 10:54 AM, Chee, Tien Fong wrote:
>>>
>>> On Wed, 2018-11-21 at 15:21 +0100, Marek Vasut wrote:
>>>>
>>>> On 11/21/2018 11:41 AM, tien.fong.chee at intel.com wrote:
>>>>>
>>>>>
>>>>> From: Tien Fong Chee <tien.fong.chee at intel.com>
>>>> Did you change Author:ship of the patch ?
>> I believe you did, so please fix that.
> Very sorry. I din't realize the author name was changed.

Please be careful next time.

>>
>>>
>>>>
>>>>>
>>>>> Bundle U-Boot fitImage containing U-Boot and FPGA bitstream
>>>>> into
>>>>> the
>>>>> u-boot-with-spl.sfp on Arria10. This lets U-Boot operate in a
>>>>> very
>>>>> similar fashion to Gen5, where the U-Boot binary got loaded by
>>>>> the
>>>>> SPL from a uImage concatenated at the end of the SPL SFP image.
>>>>> On
>>>>> Gen10, the U-Boot is in fitImage which contains the FPGA
>>>>> bitstream
>>>>> as well. In this case, the SPL can load the FPGA bitstream
>>>>> first
>>>>> and
>>>>> load the U-Boot afterward in the same manner. This is
>>>>> nonetheless a
>>>>> stopgap measure until there is a proper firmware loader in U-
>>>>> Boot.
>>>> Right, this is a stopgap measure until FW loader is present. Why
>>>> is
>>>> this
>>>> patch needed at all in this series ?
>>> This patch is cherry picked from the sdmmc_next custodian, so this
>>> patch is required for generating FIT image. I can remove the
>>> stopgap
>>> comment to avoid confusing.
>> But why is this patch needed at all ? You use the firmware loader to
>> load the FPGA bitstream. Where does the fitImage come into play ?
>>
>> The fitImage was used to circumvent the missing FW loader, when I
>> needed
>> to load multiple files (bitstream and u-boot binary). Now there is no
>> such requirement anymore, so the entire fitImage machinery is
>> probably
>> not needed ?
> Loading issue is not the reason we choose the fitImage. We choose it
> because it allows more flexibility in handling various type images,
> especially it allows user more choices to enhance integrity and
> security protection.

Do you need to load multiple images at all ? Do you need the extra
flexibility or does it only bloat and slow down the boot process for no
benefit at all? If a user needs it, they can enable it, but do we need
it by default ?

> Although we plan to use fitImage as our default implementation, but
> this series of patches are still allow fw loading individual bitstream
> image in filesystem partition. So, it is up to user to made the choice.

Right, so is the fitImage needed at all ?

-- 
Best regards,
Marek Vasut